[19p-P3-1~7] 13.3 Insulator technology

[19p-P3-6] Surface oxidation of silicon nitride films under high temperature and humid environment

〇Tomoki Oku¹, Toshihiko Shiga¹, Masahiro Totsuka¹, Hitoshi Watanabe¹ (1.Mitsubishi Electric)

Keywords:silicon nitride film,humid resistance,Molecular orbital calculation

The high temperature and humid environment degrades the humidity resistance for silicon nitride films with high density defects. The cause of the degradation is considered to be the surface oxidation. In the previous report, we showed that the NH2 molecules terminating the surface is substituted by OH molecules after the attack of H3O+ and OH- ions. In this report, we applied a molecular orbital calculation to the oxidation reaction at the 1st and 2nd layer inside from the surface of the silicon nitride film. We clarified that the reaction barrier is larger than that of OH substitution at the silicon nitride surface. Moreover, we recognized that the ion attack stretches the Si-N bonds but does not break them. Finally, we showed that the defects do not lower the reaction barrier. Therefore, we consider that the oxidation at the inside cannot be explained by the simple nucleophilic substitution reaction.